ATLANTA — The Chargers planned for this one a lot more than they had this month's previous two exhibitions.

It showed.

Playing on the road in a dome against a team intent on a good showing, the Chargers starters played their best game (half) of the preseason.

It was, in the words of quarterback Philip Rivers, “certainly better than the last couple of weeks.”

An eight-point halftime lead dwindled and ultimately disappeared in the final seconds, but the Chargers left the Georgia Dome last night feeling progress had been made.

“I like the way our guys are preparing to get ready for the season,” head coach Norv Turner said, “and I liked the way they prepared for this game and executed in the first half.”

The backups managed just a fourth-quarter field goal and couldn't stop a late 75-yard drive, as the Atlanta Falcons scored a touchdown with nine seconds remaining to steal a 27-24 victory.

“The good thing,” Turner said, “is our young players will learn the difference between winning and losing can come down to understanding one assignment and executing one assignment properly. I think there will be some great learning from this.”

In the first half, when the starting units were playing, the Chargers' pass protection was better, their kick coverage was better, their quarterback connected with his receivers and their defense overcame missed tackles and big plays to mostly thwart a good offense.

“I think we came out with a lot of energy,” linebacker Stephen Cooper said.

The Chargers did something last night they were not able to do all of 2008.

They scored a touchdown on their opening drive.

After the Falcons went out on five plays, the Chargers drove 75 yards in eight plays, scoring on a 10-yard run by Darren Sproles.

“It was good to get off to a fast start and get into the end zone on that first drive,” Rivers said. “I thought the kickoff team set the tone. They went in there and stuffed them. It was obvious we were ready to play.”

The Chargers scored the second-most points in the NFL in 2008 but just the 12th-most in the first quarter. Their 77 first-quarter points comprised their worst quarter. The Chargers' five field goals were their only opening drive points, and they were one of just two teams to not get in the end zone on a single opening drive.

“The first couple drives of a game set the tone,” Rivers said. “Not that you can't rebound from them, but we stumble around and get down 7-0, it just affects the entire game in every way.”

In a physical first half, the Chargers were sometimes run over and run through by Falcons running back Michael Turner (12 carries for 47 yards) and tight end Tony Gonzalez (two catches for 15 yards). But they stopped Atlanta on a third-and-one and limited the Falcons to a touchdown and two field goals.

The Chargers offense would not have seemed nearly as effective if not for the fact that it converted seven third-and-longs on three touchdown drives in the first half.

Penalties on the offensive line set the Chargers back, but they were saved by plays such as the pirouette and one-handed catch Vincent Jackson made on the sideline for a 32-yard gain on third-and-18, prolonging the Chargers' second scoring drive. On that drive, the Chargers converted third-and-8, third-and-13, third-and-18 and, on the touchdown, a third-and-24 screen to Michael Bennett that went for 48 yards.

“We want to stay out of those holes,” Jackson said. “But it's nice to know we have some plays in our pocket to get out of those.”

By the end of the second quarter, only the starting line was in on offense for the Chargers. Even then, left guard Kris Dielman had long since been on the sideline with a bruised shoulder. And Kynan Forney had replaced Louis Vasquez so he could get some work between Nick Hardwick and Marcus McNeill.

Only Luis Castillo and Ogemdi Nwagbuo among the defensive starters remained in the game beyond halftime. Larry English replaced Shawne Merriman early in the second quarter.

LaDainian Tomlinson did not play, and Darren Sproles was done after a first quarter in which he caught three passes for 29 yards and carried three times for 16 yards.

Rivers left the game after the pass to Bennett, having completed 10 of his 15 passes for 185 yards and a touchdown. He was sacked once.